Osmium-Catalyzed Dihydroxylation of Olefins Using Dioxygen or Air as the Terminal Oxidant

Article abstract of DOI:10.1021/ja000802u

The osmium-catalyzed dihydroxylation of various olefins using molecular oxygen or air as the stoichiometric oxidant is reported. Aromatic olefins yield the corresponding diols in good to excellent chemoselectivities under optimized pH conditions (pH = 10.4-12.0). Air can be used under moderate pressures (3-9 bar) instead of dioxygen as the reoxidant. By increasing the oxygen content of the solution, it is possible to achieve highly efficient conversion at low catalyst amount (catalyst/substrate = 1:4000). Tri- and tetrasubstituted olefins are oxidized at pH > 11 to give the corresponding 1,2-diols in good to very good yields without requiring the addition of sulfonamides or other hydrolysis agents. Studies of the dihydroxylation of functionalized olefins demonstrate that the reaction conditions tolerate a variety of functional groups. In the presence of dihydroquinine or dihydroquinidine derivatives (Sharpless ligands), asymmetric dihydroxylations occur with lower enantioselectivities than tose of the classical K₃[Fe(CN)₆] reoxidation system.

Full text of DOI:10.1021/ja000802u

J. Am. Chem. Soc. 2000, 122, 10289-10297
10289
Osmium-Catalyzed Dihydroxylation of Olefins Using Dioxygen or
Air as the Terminal Oxidant
Christian Do1bler, Gerald M. Mehltretter, Uta Sundermeier, and Matthias Beller*
Contribution from the Institut fu¨r Organische Katalyseforschung (IfOK) an der UniVersita¨t Rostock e.V.,
Buchbinderstrasse 5-6, D-18055 Rostock, Germany
ReceiVed March 6, 2000
Abstract: The osmium-catalyzed dihydroxylation of various olefins using molecular oxygen or air as the
stoichiometric oxidant is reported. Aromatic olefins yield the corresponding diols in good to excellent
chemoselectivities under optimized pH conditions (pH ) 10.4-12.0). Air can be used under moderate pressures
(3-9 bar) instead of dioxygen as the reoxidant. By increasing the oxygen content of the solution, it is possible
to achieve highly efficient conversion at low catalyst amount (catalyst/substrate ) 1:4000). Tri- and
tetrasubstituted olefins are oxidized at pH > 11 to give the corresponding 1,2-diols in good to very good
yields without requiring the addition of sulfonamides or other hydrolysis agents. Studies of the dihydroxylation
of functionalized olefins demonstrate that the reaction conditions tolerate a variety of functional groups. In the
presence of dihydroquinine or dihydroquinidine derivatives (Sharpless ligands), asymmetric dihydroxylations
occur with lower enantioselectivities than tose of the classical K3[Fe(CN)6] reoxidation system.
Introduction
Because of this lack of knowledge, we started a program to
develop atom efficient catalytic oxidation reactions for the
refinement of olefins. Initially, we were interested in the direct
synthesis of 1,2-diols from olefins. Special 1,2-diols, e.g.,
ethylene glycol and propylene glycol, are manufactured on a
million ton scale per annum.5 A number of 1,2-diols such as
2,3-dimethyl-2,3-butanediol, 1,2-octanediol, 1,2-hexanediol, 1,2-
pentanediol, and 1,2- and 2,3-butanediol are interesting for fine
chemical applications. At present they are produced in industry
by a two-step sequence consisting of epoxidation of the terminal
olefin with a peracid followed by hydrolysis of the resulting
epoxide.6 In addition, chiral 1,2-diols are of interest as inter-
mediates for pharmaceuticals and agrochemicals.
With regard to its general applicability, the OsO4-catalyzed
dihydroxylation of olefins7 is probably the most powerful tool
to synthesize 1,2-diols and diol derivatives (Scheme 1).
The synthetic utility of the osmium-catalyzed dihydroxylation
has been significantly enhanced in recent years. Especially the
introduction of a general catalytic asymmetric dihydroxylation
procedure by Sharpless and co-workers8 led to an increasing
number of applications in organic synthesis.9
Nearly 80% of all reactions performed in the chemical
industry are oxidations or reductions. The most economically
attractive as well as environmentally friendly oxidation reagents
for bulk oxidation processes are either air or molecular oxygen.
Current industrial processes using oxygen include the oxidation
of BTX aromatics or alkanes to give carboxylic acids and the
conversion of ethylene into ethylene oxide.1 Most oxidation
reactions in industry using oxygen are atom efficient processes,
but they require drastic conditions and often proceed via radical
processes.2 Thus, the scope of these reactions, with respect to
the substrate, is not very broad. To use oxygen for oxidation
reactions under milder conditions, synthetic organic chemists
have developed a number of methods involving the use of a
stoichiometric amount of a coreductant.3 Unfortunately, these
methods produce in general overstoichiometric amounts of
waste, which should be avoided nowadays even on a laboratory
scale. Despite the advantage of air or dioxygen as the final
oxidant, there are relatively few methods known which use
homogeneous catalysts in the presence of oxygen under mild
conditions.4
* Corresponding author. e-mail: matthias.beller@ifok.uni-rostock.de.
(1) Weissermel, K.; Arpe, H.-J. Industrielle Organische Chemie, 5th ed.;
Wiley-VCH: Weinheim, 1998.
(2) (a) Fischer, R. W.; Ro¨hrscheid F. In Applied Homogeneous Catalysis
with Organometallic Compounds; Cornils, B., Herrmann, W. A., Eds.;
VCH: Weinheim, 1996; pp 439-464. (b) Sheldon, R. A.; Kochi, J. K.
Metal-Catalyzed Oxidations of Organic Compounds; Academic Press: New
York, 1981. (c) Partenheimer, W. In The ActiVation of Dioxygen and
Homogeneous Catalytic Oxidation; Barton, D. H. R., Martell, A. E., Sawyer,
D. T., Eds.; Plenum: New York, 1993.
(3) (a) Review: Mukaiyama, T.; Yamada, T. Bull. Chem. Soc. Jpn. 1995,
68, 17-35. (b) Mandal, A. K.; Iqbal, J. Tetrahedron 1997, 53, 7641-7648.
(c) Iwahama, T.; Sakaguchi, S.; Ishii, Y. Chem. Commun. 1999, 727-728.
(4) (a) Groves, J. T.; Qinn, R. J. Am. Chem. Soc. 1985, 107, 5790-
5792. (b) Montanari, F., Casella, L., Eds. Metalloporphyrins Catalyzed
Oxidations; Kluwer: Dordrecht, 1994. (c) Marko´, J. E.; Giles, P. R.;
Tsukazaki, M.; Chelle´-Regnant, I.; Urch, C. J.; Brown, S. M. J. Am. Chem.
Soc. 1997, 119, 12661-12662. (d) Peterson, K. P.; Larock, R. C. J. Org.
Chem. 1998, 63, 3185-3189. (e) Coleman, K. S.; Lorber, C. Y.; Osborn,
J. A. Eur. J. Inorg. Chem. 1998, 1673-1675. (f) Christoffers, J. J. Org.
Chem. 1999, 64, 7668-7669.
The primary products formed by the reaction of OsO4 with
olefins are dimeric osmium(VI) glycolates, which are then able
to react further to yield a 1,2-diol and an osmium(VI) species.
(5) Worldwide production capacities for ethylene glycol in 1995: 9.7
Mio to/a; worldwide production of 1,2-propylene glycol in 1994: 1.1 Mio
to/a; Weissermel, K.; Arpe, H.-J. Industrielle Organische Chemie, 5th ed.;
Wiley-VCH: Weinheim, 1998; p 167 and p 302.
(6) (a) Szmant, H. H. Organic Building Blocks of the Chemical Industry;
Wiley: New York, 1989; p 347. (b) Pohl, G.; Gaube, H. In Ullmann’s
Encyclopedia of Industrial Chemistry; VCH: Weinheim, 1985; Vol. A1,
pp 305-320.
(7) Reviews: (a) Schro¨der, M. Chem. ReV. 1980, 80, 187-213. (b) Kolb,
H. C.; Van Nieuwenhze, M. S.; Sharpless, K. B. Chem. ReV. 1994, 94,
2483-2547. (c) Beller, M.; Sharpless, K. B. In Applied Homogeneous
Catalysis; Cornils, B., Herrmann, W. A., Eds.; VCH: Weinheim, 1996; pp
1009-1024. (d) Kolb, H. C.; Sharpless, K. B. In Transition Metals for
Organic Synthesis; Beller, M., Bolm, C., Eds.; VCH-Wiley: Weinheim,
1998; Vol. 2, pp 219-242. (e) Marko, I. E.; Svendsen, J. S. In
ComprehensiVe Asymmetric Catalysis II; Jacobsen, E. N., Pfaltz, A.,
Yamamoto, H., Eds.; Springer: Berlin, 1999; pp 713-787.
10.1021/ja000802u CCC: $19.00 © 2000 American Chemical Society
Published on Web 10/07/2000

10290 J. Am. Chem. Soc., Vol. 122, No. 42, 2000
Scheme 1. Osmylation of Olefins
Do¨bler et al.
Scheme 2. Osmium-Catalyzed Dihydroxylation of
R-Methylstyrene with Dioxygen
light.20 Recently, we reported that the osmium-catalyzed dihy-
droxylation of simple aliphatic and aromatic olefins proceed
efficiently in the presence of dioxygen.21 Outlined herein are
new applications of this oxidation reaction, e.g., the dihydroxyl-
ation of tri- and tetrasubstituted olefins as well as functionalized
olefins, dihydroxylations using air, and a study of catalyst
efficiency for this dihydroxylation procedure.
Because of the toxicity and the cost of osmium compounds,
several efficient reoxidation processes of Os(VI) have been
developed in the past. Initially chlorates10 and hydrogen
peroxide11 were applied as cooxidants, both of which lead, in
general, to reactions with low selectivity. However, very
recently, Ba¨ckvall and co-workers solved this problem elegantly
by using N-methylmorpholine together with flavin as cocatalysts
in the presence of hydrogen peroxide.12 Other reoxidants which
minimize side reactions are tert-butyl hydroperoxide in the
presence of Et4NOH13 or N-oxides such as N-methylmorpholine
N-oxide (NMO)14 (Upjohn process) and trimethylamine N-oxide.
K3[Fe(CN)6] was introduced as a reoxidant for osmium(VI)
species in 1975,15 which was re-invented in 1990.16 On the basis
of the substantial improvement of enantioselectivities in asym-
metric dihydroxylations by using K3[Fe(CN)6] as the oxidant,
industrial research led to the development of an in situ
electrochemical reoxidation of K4[Fe(CN)6].17
The most attractive reagents for the reoxidation of Os(IV)
are air or dioxygen, since they are the most inexpensive and
environmentally friendly oxidants. While former publications18
and patents19 demonstrate that in the presence of OsO4 and
oxygen mainly nonselective oxidation reactions take place, Krief
et al. designed successfully a reaction system consisting of
oxygen, catalytic amounts of OsO4 and selenides for the
dihydroxylation of R-methylstyrene under irradiation with visible
Results
Dihydroxylation of Aromatic Olefins. Aromatic olefins are
important substrates for the synthesis of pharmaceutically
interesting 1,2-diols.22 As demonstrated by our initial investiga-
tions, OsO4 catalyzes the dihydroxylation of aromatic olefins
in the presence of dioxygen. At present, the influence of the
pH value and the ligands are not known in detail for this class
of substrates. Hence, for our initial investigations we chose to
study the dihydroxylation of R-methylstyrene as a model system
(Scheme 2).
All catalytic experiments were conveniently carried out in
Schlenk tubes using an oxygen atmosphere above the solution.
A mixture of tert-butyl alcohol and water was used as the solvent
system throughout our study. The pH of the mixture was kept
constant by using different phosphate buffer systems (see
Experimental Section for details). The reactions were followed
by measuring the oxygen uptake with a graduated gas buret. In
all cases of chemoselective reactions, approximately 1 mmol
of dioxygen was consumed per 2 mmol of olefin.
In agreement with our previous results for terminal aliphatic
olefins, the dihydroxylation of R-methylstyrene is dramatically
influenced by the pH of the solution. In the absence of ligand,
the best chemoselectivity (92%) at total conversion is obtained
at pH 10.4 (Table 1, entries 1-4). The pH of the solution affects
not only the chemoselectivity but also the rate of the reaction.
The turnover frequency (TOF23) decreases from approximately
15 to 7 to 0.8 h-1 when the pH value is increased from 10.4 to
11.2 to 13.0. Interestingly, the addition of 0.5 mol % of DABCO
as ligand increases the chemoselectivity of the reaction from
92% to 97%; however the overall rate is decreased slightly (TOF
) 14 h-1 at pH 10.4, entry 5). When the amount of ligand is
increased to 1.5 mol %, a further decrease of rate is observed.
This effect is even more significant with the Sharpless ligand
(DHQD)2PHAL (TOF ) 12 h-1, entries 8, 10, 13, and 14). The
adverse effect of the ligand concentration on the reaction rate
is in contrast to the ligand accelerated catalysis principle24
observed for similar reactions using other reoxidants and is
explained by the fact that the ligand slows down the turnover-
limiting step (see Discussion).
(8) (a) Hentges, S. G.; Sharpless, K. B. J. Am. Chem. Soc. 1980, 102,
4263-4265. (b) Sharpless, K. B.; Amberg, W.; Bennani, Y. L.; Crispino,
G. A.; Hartung, J.; Jeong, K.-S.; Kwong, H.-L.; Morikawa, K.; Whang,
Z.-M.; Xu, D.; Zhang, X.-L. J. Org. Chem. 1992, 57, 2768-2771.
(9) (a) Nambu, M.; White, J. D. Chem. Commmun. 1996, 1619-1620.
(b) Mori, K.; Takikawa, H.; Nishimura, Y.; Horikiri, H. Liebigs Ann./Recueil
1997, 327-332. (c) Sinha, S. C.; Sinha, A.; Sinha, S. C.; Keinan, E. J. Am.
Chem. Soc. 1998, 120, 4017-4018. (d) Trost, B. M.; Calkins, T. L.; Bochet,
C. G. Angew. Chem., Int. Ed. Engl. 1997, 36, 2632-2635. (e) Harris, J.
M.; Keranen, M. D.; O’Doherty, G. A. J. Org. Chem. 1999, 64, 2982-
2983. (f) Corey, E. J.; Guzman-Perez, A.; Noe, M. C. J. Am. Chem. Soc.
1994, 116, 12109-12110. (g) Corey, E. J.; Guzman-Perez, A.; Noe, M. C.
J. Am. Chem. Soc. 1995, 117, 10805-10816. (h) Corey, E. J.; Noe, M. C.;
Ting, A. Y. Tetrahedron Lett. 1996, 37, 1735-1738.
(10) Hofmann, K. A. Chem. Ber. 1912, 45, 3329-3336.
(11) (a) Milas, N. A.; Sussmann, S. J. Am. Chem. Soc. 1936, 58, 1302.
(b) Milas, N. A.; Trepagnier, J.-H.; Nolan, J. T.; Iliopulos, M. I. J. Am.
Chem. Soc. 1959, 81, 4730-4733.
(12) Bergstad, K.; Jonsson, S. Y.; Ba¨ckvall, J.-E. J. Am. Chem. Soc. 1999,
121, 10424-10425.
(13) Sharpless, K. B.; Akashi, K. J. Am. Chem. Soc. 1976, 98, 1986-
1987.
(14) (a) Schneider, W. P.; McIntosh, A. V. (Upjohn) US-2.769.824, 1956;
Chem. Abstr. 1957, 51, 8822e. (b) Van Rheenen, V.; Kelly, R. C.; Cha, D.
Y. Tetrahedron Lett. 1976, 17, 1973-1976. (c) Ray, R.; Matteson, D. S.
Tetrahedron Lett. 1980, 21, 449-450.
(15) Singh, M. P.; Singh, H. S.; Arya, A. K.; Singh, A. K.; Sisodia, A.
K. Indian J. Chem. 1975, 13, 112.
(20) Krief, A.; Colaux-Castillo, C. Tetrahedron Lett. 1999, 40, 4189-
4192.
(21) Do¨bler, C.; Mehltretter, G.; Beller, M. Angew. Chem., Int. Ed. 1999,
38, 3026-3028.
(16) Minamoto, M.; Yamamoto, K.; Tsuji, J. J. Org. Chem. 1990, 55,
766-768.
(22) Selected examples: (a) Li, G.; Chang, H.-T.; Sharpless, K. B. Angew.
Chem., Int. Ed. Engl. 1996, 35, 451-454. (b) Curran, D. P.; Ko, S.-B. J.
Org. Chem. 1994, 59, 6139-6141. (c) Fang, F. G.; Xie, S.; Lowery, M.
W. J. Org. Chem. 1994, 59, 6142-6143. (d) Whang, Z.-M.; Kolb, H. C.;
Sharpless, K. B. J. Org. Chem. 1994, 59, 5104-5105. (e) Fisher, A. J.;
Kerrigan, F. Synth. Commun. 1998, 28, 2959-2968.
(23) TOF ) mol product × mol catalyst-1 × h-1
(17) (a) Gao, Y.; Zepp, C. M. (Sepracor Inc.) WO-9.317.150, 1994;
Chem. Abstr. 1994, 120, 119437j. (b) Anon. Chem. Eng. News 1994, 72,
41. (c) Torii, S.; Liu, P.; Tanak, H. Chem. Lett. 1995, 319-320.
(18) Cairns, J. F.; Roberts, H. L. J. Chem. Soc. C 1968, 640-642.
(19) (a) Celanese Corp., GB-1,028,940, 1966; Chem. Abstr. 1966, 65,
3064f. (b) Myers, R. S.; Michaelson, R. C.; Austin R. G. (Exxon Corp.)
US-4496779, 1984; Chem. Abstr. 1984, 101, P191362k.
(24) Berrisford, D. J.; Bolm, C.; Sharpless, K. B. Angew. Chem., Int.
Ed. Engl. 1995, 34, 1059-1070.

Os-Catalyzed Dihydroxylation of Olefins
J. Am. Chem. Soc., Vol. 122, No. 42, 2000 10291
Table 1. Dihydroxylation of R-Methylstyrenea
entry
ligand
L/Os
[L] [mmol/l]b
pHc
time [h]
yield [%]
selectivity [%]
ee [%]
1
2
3
4
5
6
7
8
9.5
10.4
11.2
13.0
10.4
10.4
11.2
10.4
9.5
10.4
11.2
13.0
10.4
10.4
10.4
10.4
10.4
10.4
10.4
10.4
24
12
24
24
14
16
24
16
24
20
23
24
20
20
24
68
21
21
21
24
75
92
84
9
90
92
92
40
97
97
97
96
94
96
97
45
97
97
94
93
95
96
94
98
DABCOf
DABCO
DABCO
1:1
3:1
3:1
1:1
3:1
3:1
3:1
3:1
6:1
30:1
3:1
3:1
3:1
3:1
6:1
1:1
1
3
3
1
3
3
3
3
6
30
3
3
3
3
6
100
97
97
93
96
33
96
97
10
60
34
30
14
95
96
94
98
(DHQD)2PHALg
(DHQD)2PHAL
(DHQD)2PHAL
(DHQD)2PHAL
(DHQD)2PHAL
(DHQD)2PHAL
(DHQD)2PHAL
(DHQD)2PHAL
(DHQD)2PHAL
(DHQD)2PYRh
(DHQD)2AQNi
(DHQD)PHNj
(DHQD)2PHAL
75
84
80
76
17
85
85
86
9
10
11
12
13
14
15d
16e
17
18
19
20l
88 (94)k
43 (69)k
65 (82)k
42
88
a Reaction conditions: 2 mmol of R-methylstyrene, 0.5 mol % of K2[OsO2(OH)4], 50 °C, 1 bar of O2, 25 mL of buffer solution, 10 mL of
t-BuOH. b The given concentration of the ligand is based on the assumption that the ligand is entirely located in the organic phase. c The given
value is the pH of the aqueous buffer solution at the beginning of the reaction. In most cases the pH of the aqueous phase remains constant during
reaction. d Reaction carried out at 40 °C. e 30 °C. f 1,4-Diazabicyclo[2.2.2.]octane. g Hydroquinidine 1,4-phthalazinediyl diether. h Hydroquinidine
2,5-diphenyl-4,6-pyrimidinediyl diether. i Hydroquinidine (anthraquinone-1,4-diyl) diether. j Hydroquinidine 9-phenanthryl ether. k Best ee values
reported in the literature, see ref 7. l 100 mol % of OsO4 to determine the ceiling ee.
Table 2. Dihydroxylation of R-Methylstyrene under Pressurea
entryb
pressure [bar]c
cat. [mol %]
ligand
L/Os
[L] [mmol/l]
yield [%]
selectivity [%]
ee [%]
1
2
3
4
5
6
7
8
9
3
3
5
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
DABCO
DABCO
DABCO
DABCO
3:1
3:1
3:1
3:1
3:1
1.5
1.5
1.5
1.5
1.5
1.5
3
3
1.5
1
83
95d
94
41
76
95d
86
93
94
93
71
95
95
94
93
92
95
95
93
94
93
93
5 (air)
9 (air)
3
1
3
5
5
10
DABCO
(DHQD)2PHAL
(DHQD)2PHAL
(DHQD)2PHAL
(DHQD)2PHAL
(DHQD)2PHAL
(DHQD)2PHAL
3:1
60
82
79
78
77
76
15:1
15:1
15:1
15:1
15:1
0.05
0.033
0.025
10
11
0.8
a Reaction conditions: K2[OsO2(OH)4], 50 °C, 25 mL of buffer solution (pH 10.4), 10 mL of t-BuOH, 24 h. b Entry 1, 6:5 mmol olefin; entries
7-11, 2 mmol olefin. c The autoclave was purged with O2 and then pressurized to the given value. d Reaction time 48 h.
To study the asymmetric catalytic dihydroxylation in the
presence of dioxygen, we performed several reactions using
different cinchona-derived ligands. Sharpless et al. reported an
enantioselectivity of 94% for the dihydroxylation of R-meth-
ylstyrene with (DHQD)2PHAL as the ligand using K3[Fe(CN)6]
as reoxidant at 0 °C.8b However, at 50 °C and at pH 10.4 in the
presence of 5 mol % of (DHQD)2PHAL, an enantioselectivity
of 88% ee is obtained. Table 1 (entries 8-19) shows that under
our conditions the enantioselectivity is influenced by the ligand
concentration, the temperature, and the pH value. The highest
enantioselectivities are observed at low pH, high ligand
concentration, and low temperature. Hence, at 30 °C (Os/L )
1:3; pH ) 10.4) an ee of 88% is obtained. However, at 30 °C
the reaction is significantly slower compared to 50 °C. At 50
°C, an 85% ee was realized by increasing the ligand concentra-
tion to Os/L ) 1:6. A further increase in the ligand concentration
(Os/L ) 1:30) does not lead to a further increase of enantiose-
lectivity. The ceiling ee at 50 °C was determined to be 88%
(Table 1, entry 20). Among the different cinchona alkaloid
ligands tested, the phthalazine derivative gave the best ee values
(Table 1, entries 8-16). This is similar to reactions with
K3[Fe(CN)6] as reoxidant.7d
the reaction rate is significantly improved by working at 3-10
bar of dioxygen pressure. We did not perform reactions at
dioxygen pressures above 10 bar due to safety reasons;25
however it is highly probable that at elevated pressures even
higher reaction rates are possible. It is worth noting that there
is no decrease in chemoselectivity at higher pressures compared
to those of the corresponding reaction at 1 bar.
Using a catalyst-to-substrate ratio of 1:1000 in the presence
of DABCO as ligand (Os/L ) 1:3), the reaction reaches 87%
conversion after 24 h at 3 bar, while at 5 bar total conversion
(TOF ) 39 h-1) is observed after the same time (Table 2, entries
1 and 3). Despite the low amount of OsO4, the catalyst is not
deactivated even after 24 h and the reaction proceeds to total
conversion (Table 2, entry 2). Because of the positive influence
of pressure, we thought that air would also be able to be
employed as the reoxidant. The use of air instead of dioxygen
would constitute a significant improvement with regard to safety
issues, applicability, and economics. Indeed, the catalytic
dihydroxylation takes place in the presence of air (Table 2,
entries 4 and 5). As one would expect, the rate of the reaction
is decreased; nevertheless 83% conversion (92% chemoselec-
tivity) of R-methylstyrene is observed at 9 bar within 24 h. These
Next, we were interested in the influence of the dioxygen
concentration on the catalyst efficiency. As shown in Table 2,
(25) Caution: At elevated pressures and temperatures, the t-BuOH/
oxygen vapors above the reaction mixture can enter an explosive regime.

10292 J. Am. Chem. Soc., Vol. 122, No. 42, 2000
Do¨bler et al.
preliminary results will be of special importance for larger scale
dihydroxylations (>1 kg). For laboratory syntheses on a mmol
scale, we recommend the procedure using dioxygen at atmo-
spheric pressure which is carried out more conveniently.
For the asymmetric dihydroxylations under pressure (Table
2, entries 6-11), we noted that a larger amount of ligand
(L/Os ) 15:1) is necessary, to obtain enantioslectivites of 80%
ee, when the catalyst amount is reduced to 0.1 mol % or lower.
This is explained by the fact that under given conditions
(temperature, solvents, etc.) the enantioselectivity of asymmetric
dihydroxylations is influenced by the concentration of the chiral
ligand in the organic phase.
Also in the presence of chiral ligands there is a clear
correlation between catalyst activity and dioxygen pressure. The
best catalyst turnover frequency of ca. 120 h-1 is obtained at
10 bar (Table 2, entry 11). This catalyst activity could be already
of interest for fine chemical application;26 however, the require-
ments for the application of the procedure in bulk processes
have not yet been met.
To understand the extent to which the structure of the
aromatic olefin alters the reactivity in the catalytic dihydroxyl-
ation with dioxygen, we studied the reactions of styrene,
4-methoxystyrene, 4-chlorostyrene, 2-vinylnaphthalene, 1-phen-
yl-1-cyclohexene, and trans-stilbene in detail (Table 3).
It is important to note that the chemoselectivity of the
substrates decreases in the following order: R-methylstyrene
> 4-methoxystyrene > 4-chlorostyrene > 1-phenyl-1-cyclo-
hexene > styrene > 2-vinylnaphthaline > trans-stilbene. There
is no clear correlation between the olefin structure and the
observed chemoselectivities at pH 10.4-11.2; however the
chemoselectivity decreases significantly at pH 13 for all
substrates. In general, the addition of ligands improves the
chemoselectivity toward 1,2-diols but reduces the rate of the
reaction. Except for stilbene, chemoselectivities of 78-97%
were realized under optimized conditions. In the case of
1-phenyl-1-cyclohexene and trans-stilbene, we observed that
the dihydroxylation is faster at pH 11.2 than at pH 10.4, with
or without the presence of ligands. Enantioselectivities of 89-
95% were obtained with (DHQD)2PHAL as the chiral ligand.
Again these values are smaller than those of dihydroxylations
using K3[Fe(CN)6] as the oxidant (97-99.8% ee).
Dihydroxylation of Aliphatic Olefins. Previously we have
shown that 1-octene reacts efficiently with OsO4 in the presence
of dioxygen. Initial tests with internal aliphatic olefins (trans-
5-decene, 2-methyl-2-pentene, 1-methyl-1-cyclohexene, and 2,3-
dimethyl-2-butene), however, were rather disappointing. At pH
10.4 in the presence of 3 mol % of DABCO as ligand, the
corresponding 1,2-diols were obtained in only 13-53% yields
(Table 4). The reason for these poor yields is probably the slow
hydrolysis of the corresponding sterically hindered Os(VI)
glycolates. On the basis of the positive effect of a more basic
buffer medium on the dihydroxylation of 1-phenyl-1-cyclohex-
ene, we proposed that sterically hindered olefins might react
more efficiently at higher pH values. Indeed, the reaction of
2,3-dimethyl-2-butene is significantly improved at a more basic
pH value with the yield increasing from 13% at pH 10.4 to
65% at pH 12.0 (Table 5).
excellent yields (78-95%) and chemoselectivities (80-98%)
were obtained (Table 6).
Dihydroxylation of Functionalized Olefins. As shown
above, unfunctionalized aromatic and aliphatic olefins proved
to be good substrates for the dihydroxylation reaction in the
presence of dioxygen. Clearly this new dihydroxylation proce-
dure is of significant importance to synthetic organic chemists
only, if various functional groups are tolerated. Hence, we were
interested in the reaction of functionalized olefins. So far no
dihydroxylations of functionalized olefins either in the presence
of dioxygen or air have been reported. Initial tests with cinnamic
as well as acrylic acid derivatives showed that these substrates
react only very sluggishly.27 However, as depicted in Table 7
other olefins such as allyl phenyl ether, allyl phenyl sulfide,
allyltrimethylsilane, 1H,1H,2H-perfluoro-1-octene, and 2-vinyl-
1,3-dioxolane all reacted with high chemoselectivities (84-97%)
and sometimes good enantioselectivities (up to 85%).
The selective dihydroxylation of allyl phenyl sulfide is quite
remarkable, as we observed no indication of oxidation of the
sulfur atom. In agreement with results of nonfunctionalized
terminal olefins, a pH of 10.4 provided the best results. The
observed enantioselectivities are consistent with the results of
Sharpless et al. that (DHQD)2AQN or (DHQD)2PYR ligands
give better results for terminal olefins than (DHQD)2PHAL.28
This effect is especially obvious for allyltrimethylsilane (Table
7). The low enantioselectivity (12% ee) observed for
the dihydroxylation of 1H,1H,2H-perfluoro-1-octene with
(DHQD)2PHAL compared to the reaction of 1-octene (65% ee
under similar conditions21) is surprising. Apart from electronic
changes, the different solubilities of the two compounds might
be responsible for this different behavior. However, previous
work on the asymmetric dihydroxylation of halogenated olefins
showed the opposite effect. With (DHQD)2PHAL the enanti-
oselectivity of 3,3,3-trifluoropropene (63% ee) is higher than
that of propene (35% ee).29
Discussion
At the start of this study it was unclear how general the
osmium-catalyzed dihydroxylation using dioxygen as oxidant
would be. The experimental results shown here demonstrate that
a number of different olefin classes (1,1-disubstituted olefins,
1,2-disubstituted aliphatic olefins, terminal aliphatic olefins, tri-
and tetrasubstituted olefins) and olefins with various functional
groups (-SR; -OR; -F; -Cl; -CH(OR)2; -SiR3) react with good
to excellent chemoselectivities. However, there are still sub-
strates (stilbene, acrylic acid, cinnamic acid) which cause
problems at present. In this respect it is interesting to note that
reactions of aromatic olefins with an R-hydrogen atom occur
in general with lower chemoselectivity compared to aliphatic
olefins. We assumed that the lower chemoselectivity is the result
of a subsequent oxidation of the benzylic position. To prove
whether this benzylic oxidation is also catalyzed by OsO4 or is
a simple radical reaction with dioxygen, we performed oxidation
reactions of stilbene-1,2-diol with dioxygen with and without
the presence of K2[OsO2(OH)4] (Scheme 3).
After stirring hydrobenzoin (1,2-stilbenediol) for 24 h at 50
°C under 1 bar of dioxygen at pH 10.4 (buffered solution), no
Applying 2 mol % of K2[OsO2(OH)4] as catalyst, the yield
and selectivity is nearly quantitative. In addition, other olefins
which form hydrolysis-stable Os(VI) glycolate complexes gave
increased product yields at pH 11.2-12.0. In all cases, good to
(27) In the case of acrylic acid, slow oxygen uptake indicates that some
reaction takes place; however the products could not been isolated from
the aqueous phase.
(28) Becker, H.; Sharpless, K. B. Angew. Chem., Int. Ed. Engl. 1996,
35, 448-451.
(29) (a) Vanhessche, K. P. M.; Sharpless, K. B. Chem. Eur. J. 1997, 3,
517-522. (b) Bennani, Y. L.; Vanhessche, K. P. M.; Sharpless, K. B.
Tetrahedron: Asymmetry 1994, 5, 1473-1476.
(26) Blaser, H.-U.; Pugin, B.; Spindler, F. In Applied Homogeneous
Catalysis with Organometallic Compounds; Cornils, B., Herrmann, W. A.,
Eds.; VCH: Weinheim, 1996; Vol. 2, pp 992-1009.

Os-Catalyzed Dihydroxylation of Olefins
J. Am. Chem. Soc., Vol. 122, No. 42, 2000 10293
Table 3. Dihydroxylation of Aromatic Olefinsa
a Reaction conditions: 2 mmol of olefin, 1 mol % of K2[OsO2(OH)4], 50 °C, 1 bar ofo O2, 25 mL of buffer solution, 10 mL of t-BuOH, 24 h.
b 1 mmol of trans-stilbene, 15 mL of buffer solution, 20 mL of t-BuOH, 24 h. c 2 mol % of K2[OsO2(OH)4].
significant conversion of the diol was observed as shown by
no dioxygen uptake. Similar reactions in the presence of 1 mol
% of K2[OsO2(OH)4] revealed a total conversion of the diol
after 24 h at 50 °C and pH 10.4, yielding mixtures of benzoic
acid, benzaldehyde, and other oxygenated products. Thus, OsO4
also catalyzes the oxidative cleavage of aromatic 1,2-diols.
Again, this reaction is strongly pH dependent and is favored
by two R-aryl substituents. Further studies of this reaction are
currently underway.
by Sharpless et al. for the osmium-mediated dihydroxylation
with K3[Fe(CN)6] as the reoxidant (Scheme 4). There is
obviously only a minor involvement of a second catalytic cycle
as suggested for the dihydroxylation with NMO, with the
intermediate Os(VI) glycolate being oxidized to a Os(VIII)
species prior to hydrolysis.30 Such a second cycle would lead
to significantly lower enantioselectivities, as the attack of a
second olefin molecule on the Os(VIII) glycolate occurs in the
absence of chiral ligand. As outlined above, the observed
enantioselectivities for the dihydroxylation with oxygen are
lower but close to the data previously published by the Sharpless
With regard to the mechanism of the described dihydroxyl-
ation, we propose a catalytic cycle similar to the one presented

10294 J. Am. Chem. Soc., Vol. 122, No. 42, 2000
Table 4. Dihydroxylation of Aliphatic Olefinsa
Do¨bler et al.
system. The more basic the solution becomes the lower the
obtained enantioselectivity is (Table 3, entries 6-10). We
explain this behavior by a competition between hydroxide ions
and the chiral hydrochinidine derivatives, both acting as ligands
toward the central Os atom. Apparently, the reaction of olefin
with nonchiral osmium hydroxide complexes is competitive to
the reaction with osmium alkaloid complexes at a strong basic
pH (>12).
Especially noteworthy is the retarding effect of the ligand
observed for the dihydroxylation of aromatic olefins. We
propose that for these olefins neither the reaction of the OsO4-
ligand complex with the olefin nor the hydrolysis of the Os-
(VI) glycolate is the rate-determining step of the catalytic cycle
(Scheme 4). In agreement with the increased turnover frequency
at higher oxygen pressure, the reoxidation of the Os(VI) hydroxy
species is most likely the critical reaction step. Apparently this
reoxidation is inhibited by ligands.
The significant influence of the pH between 9.5 and 12 on
the catalyst productivity is explained by the formation of anionic
Os(VI) hydroxide species and a faster hydrolysis of Os(VI)
glycolates. In principle, more basic anionic Os(VI) hydroxide
complexes should be more easily oxidized compared to neutral
species.31 The slow and nonselective dihydroxylation of tri-and
tetrasubstituted olefins at pH 10.4 demonstrates that the hy-
drolysis step of the Os(VI) glycolate complexe is rate determin-
ing for this class of sterically hindered olefins. However, by
simply making the reaction solution more basic, this hydrolysis
becomes very efficient. For the future one would expect that
the careful control of pH value will lead to efficient dihydroxyl-
ations of all kinds of sterically hindered olefins independent
from the oxidant.
a Reaction conditions: 2 mmol of olefin, DABCO/osmium ) 3:1,
50 °C, 1 bar of O2, 25 mL of buffer solution (pH 10.4), 10 mL of
t-BuOH, 18 h.
Table 5. Dihydroxylation of 2,3-Dimethyl-2-butene at Different
pH Valuesa
pH
cat. [mol %]
yield [%]
sel. [%]
10.8
11.2
12.0
13.0
12.0
1
1
1
1
2
23
51
65
41
94
31
81
88
69
99
When the reactions proceed with high chemoselectivity, two
molecules of diol are produced out of one molecule of dioxygen.
Therefore, this method represents one of the rare cases of 100%
atom economic oxidation reactions applying dioxygen as the
oxidant.
a Reaction conditions: 2 mmol of 2,3-dimethyl-2-butene, ligand/
osmium ) 3:1, 50 °C, 1 bar of O2, 25 mL of buffer solution, 10 mL
of t-BuOH, 18 h.
Conclusion
The use of dioxygen in selective oxidation reactions for the
synthesis of fine chemicals in an environmentally friendly way
is an important challenge in catalysis. We have demonstrated
that Os-catalyzed dihydroxylations of various olefins can be
performed efficiently in the presence of dioxygen or air. Using
R-methylstyrene as a model substrate, it is shown that in the
presence of very small catalyst-to-substrate ratios (up to 1:4000)
high yields of the corresponding 1,2-diol are possible at slightly
elevated oxygen pressures. Even sterically hindered 1,2-di, tri-,
and tetrasubstituted olefins are dihydroxylated, without the need
for addition of stoichiometric amounts of a hydrolyzing agent
such as methanesulfonamide. In the presence of chiral dihyd-
roquinidine or dihydroquinine derivatives (Sharpless ligands),
asymmetric dihydroxylations take place, albeit with lower
enantioselectivities compared to those obtained under the
Sharpless AD conditions.
group, despite the higher reaction temperature (50 °C vs 0 °C).
This is an indication that the direct oxidation of the Os(VI)
glycolate to an Os(VIII) glycolate is no major pathway under
the described reaction conditions. To compare dioxygen with
K3[Fe(CN)6] more precisely, we performed the catalytic dihy-
droxylation of R-methylstyrene with both reoxidants at 50 °C
at pH 10.7 in the presence of 1.5 mol % and 5 mol % of
(DHQD)2PHAL. The use of K3[Fe(CN)6] gave an enantiose-
lectivity of 87 and 88% ee, respectively. In the presence of
dioxygen an ee of 80% (1.5 mol % of (DHQD)2PHAL) and
85% (5 mol % of (DHQD)2PHAL) was obtained. Further
increase of the ligand concentration does not lead to the ceiling
ee (88%) at this temperature. Therefore it appears that dioxygen
is a lower selective oxidant compared to K3[Fe(CN)6]. Never-
theless the Os(VI) hydroxide complexes should be mainly
oxidized by dioxygen, but not the intermediate Os(VI) glyco-
lates.
Experimental Section
With most substrates, differences in the stereoselective
induction were observed compared to the use of K3[Fe(CN)6]
as terminal oxidant, but the ligand-olefin structure relationship
is similar to previously reported results. However, we observed
some interesting details in the present system: the enantiose-
lectivity is strongly dependent on the pH value of the buffer
General. 1H and 13C NMR spectra were recorded on a Bruker ARX
400 spectrometer (1H 400.1 MHz, 13C 100.6 MHz). Chemical shifts
(δ) are given in ppm and refer to residual solvent as internal standard.
Gas chromatography was performed on a Hewlett-Packard HP 6890
chromatograph with a HP5 column. Mass spectra were recorded on a
AMD 402/3 mass spectrometer. The products were purified on silica
(30) Wai, J. S. M.; Marko´, I.; Svendsen, J. S.; Finn, M. G.; Jacobsen, E.
N.; Sharpless, K. B. J. Am. Chem. Soc. 1989, 111, 1123-1125.
(31) Pe´richon, J.; Palous, S.; Buvet, R. Bull. Soc. Chim. Fr. 1963, 982-
988.

Os-Catalyzed Dihydroxylation of Olefins
J. Am. Chem. Soc., Vol. 122, No. 42, 2000 10295
Table 6. Dihydroxylation of Aliphatic Olefins under Optimized pH Conditionsa
a Reaction conditions: 2 mmol of olefin, ligand/osmium ) 3:1, 50 °C, 1 bar of O2, 25 mL of buffer solution, 10 mL of t-BuOH, 18 h.
Table 7. Dihydroxylation of Functionalized Olefinsa
Scheme 3. Osmium-Catalyzed C-C Cleavage of
1,2-Diphenyl-1,2-ethanediol
Scheme 4. Proposed Catalytic Cycle for the
Dihydroxylation of Olefins with OsO4 and Oxygen as the
Terminal Oxidant
either determined by HPLC of the isolated diol or its bisbenzoate
derivative. The retention time of the major HPLC peak is printed in
bold. The absolute configurations of the products were either determined
by comparison with original samples or are based on the mnemonic
device established by Sharpless et al.32
Dihydroxylation of r-Methylstyrene under Atmospheric Oxygen
a Reaction conditions: 2 mmol of olefin, 50 °C, 1 bar of O2, 25 mL
Pressure (Typical Procedure). In a 100 mL Schlenk tube, 3.7 mg
of buffer solution (pH 10.4), 10 mL of t-BuOH, 18 h, 1 mol % of
(0.01 mmol) of K2[OsO2(OH)4] and 23.4 mg (0.03 mmol) of
K2[OsO2(OH)4] for allyl phenyl ether, allyl phenyl sulfide, and
(DHQD)2PHAL were dissolved in a mixture of 10 mL of t-BuOH and
25 mL of anaqueous buffer solution (pH 10.4).33 The Schlenk tube
was then purged with oxygen, and the biphasic mixture was warmed
to 50 °C in an oil bath. Then R-methylstyrene (260 µL, 2 mmol) was
added in one portion by a syringe and the tube connected to a graduated
allyltrimethylsilane, 2 mol % of K2[OsO2(OH)4] for 1H,1H,2H-
perfluoro-1-octene and 2-vinyl-1,3-dioxolane, ligand/osmium ) 3:1.
b Ligand/osmium 1.5:1. c 14 h. d 7 h.
gel 60, 230-400 mesh (Merck). High-performance liquid chromatog-
raphy was carried out using a Hewlett-Packard HP 1090 liquid
chromatograph equipped with a DAD. Enantiomeric excess values were
(32) Kolb, H. C.; Andersson, P. G.; Sharpless, K. B. J. Am. Chem. Soc.
1994, 116, 1278-1291.

10296 J. Am. Chem. Soc., Vol. 122, No. 42, 2000
Do¨bler et al.
gas buret filled with oxygen. The reaction mixture was stirred vigorously
with a magnetic stirring bar, and the reaction was followed by observing
the oxygen uptake.
1-Phenyl-1,2-cyclohexanediol. 1H NMR (CDCl3): δ ) 1.35-1.89
(m, 11H), 3.96 (dd, J ) 4.7, 11.1 Hz, 1H), 7.21-7.53 (m, 5H); 13C
NMR: δ ) 21.1, 24.3, 30.9, 38.5, 74.5, 75.7, 125.1, 127.0, 128.5, 146.3;
MS (EI, 70 eV), m/e: 192 ([M]+, 59), 174 (20), 145 (10), 133 (100),
120 (36), 107 (5), 105 (68), 91 (18), 77 (36), 55 (26); HPLC (diol):
Whelk (25 cm × 0.46 cm i.d.), 10% iPrOH in hexane, flow rate 1.0
mL/min, tR ) 4.4 (S, S), tR ) 6.4 (R, R).
After 24 h, 22 mL (ca. 1 mmol) of oxygen was consumed.34 A small
amount of Na2SO3 was added and the mixture was cooled to room
temperature under stirring. The mixture was then extracted twice with
20 mL portions of ethyl acetate. The combined organic layers were
dried over MgSO4 and submitted for GC analysis after addition of 100
µL of diethylene glycol di-n-butyl ether as an internal GC standard.
For isolation of the product, the solvent was removed under reduced
pressure and the crude diol purified by column chromatography (hexane/
ethyl acetate 2:1) to give 257 mg (93%) of 2-phenyl-1,2-propanediol
as a white solid. HPLC analysis of the pure diol showed an enantiomeric
excess of 88%.
1-(2-Naphthyl)-1,2-ethanediol. 1H NMR (d6-DMSO): δ ) 3.64 (t,
J ) 5.9 Hz, 2H), 4.80-4.84 (m, 1H), 4.88 (t, J ) 5.9 Hz, 1H), 5.49
(d, J ) 4.2 Hz, 1H), 7.58-7.98 (m, 7H); 13C NMR: δ ) 68.4, 75.0,
120.0, 125.7, 126.1, 126.6, 127.0, 128.3, 128.8, 133.4, 133.9, 142.2;
MS (EI, 70 eV), m/e: 188 ([M]+, 5), 157 (100), 129 (88), 128 (37),
127 (22), 31 (6); HPLC (diol): Kromasil KR100-5CHI-TBB, 3% iPrOH
in hexane, flow rate 0.3 mL/min, tR ) 50.0 (S), tR ) 53 (R).
1,2-Diphenyl-1,2-ethanediol. 1H NMR (CDCl3): δ ) 2.73 (brs, 2H),
4.69 (s, 2H), 7.09-7.22 (m, 10H); 13C NMR: δ ) 79.1, 126.9, 127.9,
128.1, 139.8; MS (EI, 70 eV), m/e: 214 ([M]+, 1), 197 (14), 108 (100),
107 (89), 79 (78), 77 (40), 51 (11); HPLC (diol): Daicel Chiralcel
OB-H, 10% EtOH in hexane, flow rate 1.0 mL/min, tR ) 8.0 (R,R),
10.1 (S,S).
Dihydroxylation of 2-Vinyl-2,3-dioxolane. 2-Vinyl-2,3-dioxolane
(200 µL, 2 mmol) was reacted with 14.7 mg (2 mol %) of K2[OsO2-
(OH)4] and 93.6 mg (6 mol %) of (DHQD)2PHAL as described above.
After 18 h, 15 mL of oxygen was consumed. For workup, the reaction
mixture was extracted once with 20 mL of ethyl acetate and the amount
of unreacted olefin was determined by GC analysis of the organic layer
with diethylene glycol di-n-butyl ether as an internal GC standard. The
aqueous layer was concentrated under reduced pressure and the residue
extracted with 25 mL of EtOH. After filtration, the solvent was
evaporated and the resulting crude diol purified by column chroma-
tography (CHCl3/MeOH 6:1) to yield 169 mg (63%) of 2-(1,2-
dihydroxyethyl)-1,3-dioxolane as a colorless oil. HPLC analysis of the
bisbenzoate derivative gave an enantiomeric excess of 23%.
1
5,6-Decanediol. H NMR (CDCl3): δ ) 0.89 (t, J ) 7.2 Hz, 6H),
1.28-1.50 (m, 12H), 2.12 (s, 2H), 3.37-3.39 (m, 2H); 13C NMR: δ
) 14.0, 22.7, 27.8, 33.3, 74.5; MS (CI, isobutane), m/e: 175 ([M +
H]+, 2), 157 ([M - OH]+, 100), 139 (15), 117 (2), 97 (5), 87 (12), 86
(11), 83 (14), 69 (19); HPLC (bisbenzoate): Daicel Chiralcel OD-H,
0.2% iPrOH in hexane, flow rate 1.0 mL/min, tR ) 6.0 (S,S), tR ) 7.3
(R,R).
1-Methyl-1,2-cyclohexanediol. 1H NMR (CDCl3): δ ) 1.18-1.78
(m, 11H), 1.96 (brs, 2H), 3.37 (dd, J ) 3.7, 9.1 Hz, 1H); 13C NMR:
δ ) 21.5, 23.1, 26.5, 30.4, 36.8, 71.5, 74.8; MS (EI, 70 eV), m/e: 130
([M]+, 12), 112 (19), 97 (24), 83 (12), 71 (100), 58 (41), 43 (76); HPLC
(bisbenzoate): Daicel Chiralcel OD-H, 1% iPrOH in hexane, flow rate
1.0 mL/min, tR ) 11.5 (1R, 2S), tR ) 13.1 (1S,2R).
Dihydroxylation of r-Methylstyrene under Elevated Pressure.
In a 200 mL steel autoclave (Roth GmbH), equipped with a magnetic
stirrer and a glass inline, 0.1 mol % of K2[OsO2(OH)4] (1.0 mL of a
freshly prepared 2 mmol/L solution in aqueous buffer) and 23.4 mg
(1.5 mol %) of (DHQD)2PHAL were dissolved in a mixture of 25 mL
of an aqueous buffer solution (pH 10.4) and 10 mL of t-BuOH. The
autoclave was purged with oxygen and 260 µL (2 mmol) R-methyl-
styrene was added. Then the autoclave was closed, pressurized with
oxygen, and heated to 50 °C. After 24 h, the reaction mixture was
worked up as described above to yield 251 mg (91%) of 2-phenyl-
1,2-propanediol (79% ee).
Physical Data for Diols: 2-Phenyl-1,2-propanediol. 1H NMR
(CDCl3): δ ) 1.50 (s, 3H), 2.39 (brs, 2H), 3.58 (d, J ) 11.1 Hz, 1H),
3.74 (d, J ) 11.1 Hz, 1H), 7.23-7.41 (m, 5H); 13C NMR: δ ) 26.0,
71.0, 74.8, 125.0, 127.1, 128.4, 144.9; MS (EI, 70 eV), m/e: 152 ([M]+,
2), 135 (2), 121 (88), 105 (5), 91 (6), 77 (10), 51 (5), 43 (100), 31 (3);
HPLC (diol): (R,R)-Whelk-O1, 2% EtOH in hexane, flow rate 1.0 mL/
min, tR ) 14.4 (S), 16.7 (R).
1
2-Methyl-2,3-pentanediol. H NMR (CDCl3): δ ) 0.98 (t, J )
7.3 Hz, 3H), 1.09 (s, 3H), 1.14 (s, 3H), 1.20-1.33 (m, 1H), 1.42-
1.53 (m, 1H), 3.23 (dd, J ) 2.2, 10.5 Hz, 1H), 3.34 (brs, 2H); 13C
NMR: δ ) 11.3, 22.9, 24.5, 26.4, 73.3, 80.2; MS (CI, isobutane),
m/e: 119 ([M + H]+, 2), 101 ([M - OH]+, 100), 83 (11), 71 (12), 60
(7); HPLC (bisbenzoate): Daicel Chiralcel OD-H, 0.3% iPrOH in
hexane, flow rate 1.0 mL/min, tR ) 11.5 (S, S), tR ) 13.0 (R,R).
1
2,3-Dimethyl-2,3-butanediol. H NMR (CDCl3): δ ) 1.21 (s, 12
H), 2.04 (s, 2H); 13C NMR: δ ) 24.8, 75.0; MS (EI, 70 eV), m/e: 85
([M - H2O - CH3]+, 22), 59 (100), 57 (62), 43 (54).
3-Phenoxy-1,2-propanediol. 1H NMR (CDCl3): δ ) 2.10 (brs, 2H),
3.74 (dd, J ) 5.2, 11.3 Hz, 1H), 3.83, (dd, J ) 3.7, 11.3 Hz, 1H),
3.99-4.12 (m, 3H), 6.85-7.29 (m, 5H); 13C NMR: δ ) 63.7, 69.1,
70.3, 114.5, 121.3, 129.6, 158.3; MS (EI, 70 eV), m/e: 168 ([M]+,
27), 119 (9), 94 (100), 77 (17); HPLC (diol): Daicel Chiralcel OD-H,
20% iPrOH in hexane, flow rate 1.0 mL/min, tR ) 6.7 (R), tR ) 11.9
(S).
1-Phenyl-1,2-ethanediol. 1H NMR (CDCl3): δ ) 2.6 (s, 2H), 3.63
(dd, J ) 8.2, 11.4 Hz, 1H), 3.72 (dd, J ) 3.6, 11.4 Hz), 4.79 (dd, J )
3.6, 8.2 Hz, 1H), 7.28-7.34 (m, 5H); 13C NMR: δ ) 68.0, 74.7, 126.0,
128.0, 128.5, 140.4; MS (EI, 70 eV), m/e: 138 ([M]+, 9), 121 (14),
107 (100), 79 (56), 77 (29), 51 (6), 31 (4); HPLC (diol): Daicel
1
(2,3-Dihydroxypropyl) Phenyl Sulfide. H NMR (CDCl3): δ )
Chiralcel OB-H, 5% iPrOH in hexane, flow rate 1.0 mL/min, tR
12.5 (R), 16.2 (S).
)
2.28 (brs, 2H), 2.92 (dd, J ) 8.1, 13.9 Hz, 1H), 3.04 (dd, J ) 4.6, 13.9
Hz, 1H), 3.51 (dd, J ) 5.6, 11.1 Hz, 1H), 3.67-3.74 (m, 2H), 7.16-
7.34 (m, 5H); 13C NMR: δ ) 37.8, 65.1, 69.7, 126.8, 129.1, 130.1,
134.8; MS (EI, 70 eV), m/e: 184 ([M]+, 46), 152 (7), 135 (32), 123
(44), 110 (100), 91 (24), 65 (18), 45 (30); HPLC (diol): Daicel Chiralcel
OD-H, 5% EtOH in hexane, flow rate 1.0 mL/min, tR ) 14.2 (S), tR )
16.0 (R).
1-(4-Methoxyphenyl)-1,2-ethanediol. 1H NMR (CDCl3): δ ) 2.25
(brs, 2H), 3.60-3.72 (m, 2H), 3.78 (s, 3H), 4.75 (dd, J ) 3.8, 8.1 Hz,
1H), 6.82-7.31 (m, 4H); 13C NMR: δ ) 54.3, 67.0, 73.3, 112.9, 126.3,
131.6, 158.4; MS (EI, 70 eV), m/e: 168 ([M]+, 7), 138 (9), 137 (100),
77 (24); HPLC (diol): Daicel Chiralcel OB, 10% iPrOH in hexane,
flow rate 2.0 mL/min, tR ) 13.6 (R), tR ) 16.7 (S).
1
3-(Trimethylsilyl)-1,2-propanediol. H NMR (CDCl3): δ ) 0.01
1
1-(4-Chlorophenyl)-1,2-ethanediol. H NMR (CDCl3): δ ) 2.49
(s, 9H), 0.65 (dd, J ) 4.4, 14.5 Hz, 1H), 0.76 (dd, J ) 8.1, 14.5 Hz,
1H), 3.28 (dd, J ) 8.4, 11.0 Hz, 1H), 3.40-3.58 (m, 2H), 3.68-3.86
(m, 2H); 13C NMR: δ ) -0.9, 21.5, 68.9, 70.3; MS (CI, isobutane),
m/e: 149 ([M + H]+, 1), 131 ([M - OH]+, 77), 115 (11), 91 (15), 75
([M - Si(CH3)3)]+, 100), 73 (21); HPLC (bisbenzoate): Daicel
(s, 2H), 3.56-3.73 (m, 2H), 4.77 (dd, J ) 3.4, 8.3 Hz, 1H), 7.26-
7.32 (m, 4H); 13C NMR: δ ) 68.3, 74.4, 127.9, 129.1, 134.2, 139.3;
MS (EI, 70 eV), m/e: 172 ([M]+, 8), 141 (100), 77 (93); HPLC (diol):
Daicel Chiralcel OD-H, 3% iPrOH in hexane, flow rate 1.0 mL/min,
tR ) 29.9 (R), tR ) 35.1 (S).
Chiralcel OD-H, 0.2% EtOH in hexane, flow rate 1.0 mL/min, tR
)
9.3 (S), tR ) 10.5 (R).
1
(33) The different buffer solutions were prepared as follows: 34.0 g of
potassium dihydrogen phosphate were dissolved in 500 mL of water and
the pH of the solution was then adjusted to the desired value by addition of
the required amount of 2 N NaOH.
(34) When reactions are of low selectivity, a greater amount of oxygen
is consumed.
1H,1H,2H-Perfluorooctane-1,2-diol. H NMR (d6-DMSO): δ )
3.74 (m, 1H), 3.93 (m, 1H), 4.30 (m, 1H), 5.24 (s, 1H), 6.49 (s, 1H);
13C NMR: δ ) 60.2, 76.9, 110.2, 110.9, 112.9, 115.3, 116.8, 119.4;
MS (CI, isobutane), m/e: 381 ([M + H]+, 100), 363 ([M - OH]+,
24), 330 (2), 273 (1), 154 (7), 111 (11); HPLC (bisbenzoate): Daicel

Os-Catalyzed Dihydroxylation of Olefins
J. Am. Chem. Soc., Vol. 122, No. 42, 2000 10297
Chiralcel OD-H, 0.15% EtOH in hexane, flow rate 1.0 mL/min, tR
7.1 (S), tR ) 8.0 (R).
)
Stahr for excellent technical support and Dr. C. Fischer for her
continuous help with the HPLC analysis. Dr. H. Hugl, Dr. C.
Militzer, and Dr. M. Eckert (Bayer AG) are thanked for general
discussions. We also thank Dr. M. Hateley for help with this
manuscript and Prof. Dr. K. B. Sharpless for helpful comments.
Financial support from Bayer AG and the Ministry of Education,
Science and Cultural Affairs of Mecklenburg-Vorpommern is
gratefully acknowledged.
2-(1,2-Dihydroxyethyl)-1,3-dioxolane. 1H NMR (CDCl3): δ ) 2.86
(s, 2H), 3.67-3.75 (m, 3H), 3.86-4.02 (m, 4H), 4.88 (d, J ) 3.4 Hz,
1H); 13C NMR: δ ) 62.6, 65.1, 65.3, 71.8, 103.7; MS (EI, 70 eV),
m/e: 117 ([M - OH]+, 10), 73 (100), 45 (41), 31 (11), 29 (11); HPLC
(bisbenzoate): Daicel Chiralpak AD, 5% EtOH in hexane, flow rate
1.0 mL/min, tR ) 22.0 (R), tR ) 30.4 (S).
Acknowledgment. Dedicated to Prof. Dr. Gu¨nther Wilke
on the occasion of his 75th birthday. The authors thank Mrs. I.
JA000802U